1. Field of the Invention
This invention relates to an apparatus and method for testing and exercising cervical or neck muscles, and more particularly to such an apparatus and method in which a user is in a seated position and exerts a head motion against a head pad for the testing and exercising of the cervical muscles.
2. Description of Prior Art
The human spine, specifically the neck, is subject to numerous external forces that produce damage to the support structures that are responsible for the maintenance of the mechanical integrity. This area called the cervical or c-spine, while subject to invasive tumors, infection or metabolic disease is more often traumatized by external forces than internal pathology.
The wear and tear of daily living takes its toll on the muscles, tendons and ligaments which in turn may result in erratic motion between one vertebrae and the next. Impact trauma or repetitive stress likewise produces neck pain while instability allows pinching of adjacent nerves or never fibers. Even though a dysfunctional spine may not produce pain, when it becomes dysfunctional, the instability usually produces pain.
From the standpoint of stability, muscular tonicity has a dynamic role in the mechanical integrity necessary for dynamic motion of the cervical spine. When this strength or muscular tone is lost due to impact trauma or repetitive stress, individual joint stability is likewise lost. If the spine is only as strong as the muscles that give it support, a correlation exists between paraspinal muscular strength and normal function. Pain resulting from instability and dysfunction usually occurs at the nerve rootlets as they exit the spinal cord and are subject to compression, pinching and indirect facilitated pressure.
Inactivity of muscles or limitation of joint movement also results in muscular disuse atrophy. This atrophy represents loss of strength. While the immobilization of joints limits the pain associated with motion it also perpetuates the loss of strength. Treatment of neck pain includes a variety of remedies to reduce pain. A non-medical, non-invasive and safe exercise program is frequently recommended by physicians in order to compensate for the strength loss during inactivity and recovery.
Heretofore, such as shown in U.S. Pat. No. 5,002,269 dated Mar. 26, 1991, an apparatus has been provided for testing and exercising cervical or neck muscles in which a user is seated with the upper torso below the neck immobilized and the head positioned against a head pad on a movement arm pivotable about a generally horizontal axis. The movement arm is urged against movement in a rearward direction by a freely yieldable resistance weight. The user's cervical muscles produce a force to cause the head to move rearwardly to pivot the movement arm rearwardly against the resistance weight which is lifted as the movement arm is pivoted rearwardly. The subject's head is then moved forwardly causing the movement arm under the force of the resistance weight to pivot forwardly as the resistance weight descends. The exercise is repeated until the subject is no longer able to pivot the movement arm rearwardly. To test the static strength of the cervical muscles in the apparatus of U.S. Pat. No. 5,002,269, the movement arm is fixed in several different angular positions and in each position the subject exerts a force for pressing the head rearwardly against the movement arm, and the magnitude of the force is measured and recorded. Once the static strength of the subject's cervical muscles is determined, a safe resistance weight less than the static strength of the muscles, is chosen to be used in the dynamic test or exercise.
U.S. Pat. No. 4,989,859 dated Feb. 5, 1991 discloses a method of exercising rotary neck muscles of the human body including providing a head pad assembly mounted for rotary movement about a vertical axis and having a pair of opposed spaced pads engaging opposite sides of the head of the user while the torso is immobilized below the neck. The user turns or twists his head from one side to the other and a resistance weight is operatively connected to a frame for the head pad assembly to resist rotary motion of the head.
U.S. Pat. No. 4,768,779 dated Sep. 6, 1988 shows a neck exercise apparatus in which the head of a user is positioned within a helmet and a hydraulic actuator resists movement of the helmet. A strain gauge is provided to measure static testing of the neck upon pivotal locking of the helmet against movement.